Parallel roll adjustment mechanism



June 26, 1951 W, C, sTElNME-rz 2,558,321

PARALLEL ROLL ADJUSTMENT MECHANISM Filed Oct. 30, 1948 4 Sheets-Sheet 2 Ell?. 2

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/fa//zzg June 26, 1951 w. c. sTExNME-rz PARALLEL ROLL ADJUSTMENT MECHNISM 4 Sheets-Sheet 3 Filed Oct. 30, 1948 OOP a hwr@ /NVENTo/Q WALTER C. STemmi-zTz,

BY JM/4m Patented June 26, 1951 PARALLEL ROLL'ADJ USTMEN T MECHANISM Walter C. Steinmetz, Columbus, Ohio, assignor to The Jeffrey Manufacturing Company, a corporation of Ohio Application October 30, 1948, Serial No. 57,557

2 claims.

My invention relates to Crushers and more particularly to Crushers of the type wherein the proximity of a crushing roll, rotor or element is adjustable with respect to a crushing `or break- Briey described, the Crusher shown in the drawings embodies the features of my invention and it is a double roll crusher including a main frame I that forms a crushing compartment ing element co-operating therewith. v5 or chamber II in which there are two power An object of my invention is to provide an driven crushing rolls I2 and I3 that co-operate improved Crusher of the above mentioned type. to crush friable material such, for example, as Another object of my invention is to provide coal, iron ore and the like, that is fed to the an improved crusher of the above mentioned crushing rolls I2 and I3 through a feed chute I4. type wherein mechanism is provided for main- The crushing roll I2 is a fixed crushing roll, taining the axis of a crushing roll, rotor, or elethat is, its shaft I5 is carried for rotation at ment parallel with respect to a co-operating each end by bearing assemblies that are removcrushing or breaking element while the proximity ably fixed to the main frame II) and the crushof the roll, rotor or element moves or is adjusted ing ro-ll I3 is bodily movable toward and away with respect to said co-operating crushing elefrom the fixed crushing roll I2 along a plane. ment- The movable crushing roll I3 is carried for rota- Another and more specific object of my invention adjacent each end of its shaft I6 by beartion is to provide an improved Crusher including ing assemblies that are slidably mounted to the a crushing roll, rotor or element the axis of which main frame I0. The proximity of the movable is movable in a plane intersecting a co-operatcrushing roll I3 with respect to the xed crushing crushing or breaking element and wherein ing roll I2 is adjustable by mechanism which is the crushing roll is urged toward said oo-operatfully described hereinafter. The ends of the ing breaking element for reducing material theremovable crushing roll I 3 are interconnected between with an improved linkage or motion through the bearing assemblies which support mechanism for positively causing the ends of the ends of its shaft I6 by parallel motion mechathe crushing roll to travel in said plane through nisms that maintain the axis of the movable roll equal distances When the T011 mOVeS With respect I3 at all times parallel with the axis of the shaft t0 Said CO-Operating crushing element particui5 of the fixed roll lz. These parallel motion ieliy While Crushing material. mechanisms above referred to are also described Other objects of my invention will appear hereinafter. hereinafter the novel features and combinations The construction of the crusher lshown 1n the being set forth in the appended claims. drawings will best be understood 1f features 0f In tile eCCOmDeDYiDg drawings, construction of the main frame I0 are rst de- Fig. 1 is a view in plan of a double roll crusher scribed. Therefore reference 1s now made to embodying features of my invention, parts of Figs. 8 and 9 of the drawings `wherein the main the crusher being broken away and parts thereof frame I0 is shown by itself. The main frame I0 being indicated, for the sake of clarity, in dotis generally symmetrical about a plane taken verdash lines; tioally through its longitudinal center. Along Fig. 2 is a side view in elevation with parts opposite sides it includes laterally spaced base or broken away tc show structure of the apparatus mounting plates I l. Along the inner edges of Seen in Fig 1; each base plate II there is welded 1n a vertical Figs. 3, 4 and 5 are sectional detail views, the position a side frame plate I8 which plates IB SeCiOIlS being taken Oil lines 33, 4 4 and form the sides of the crushing chamber or coinv5 5, respectively, 0f Fgl; partment II. The side frame plates I8 terminate Fie- 6 iS e 130D eleVeiiOnei View 0f One half 0f 45 short of the ends of the base plates I1 and the the Crusher Seen in Figs. 1 and 2 with Celifeil sides of the main frame I0 including the base parte leHlOVed and Certain Peris bIOkeD away; plates I'I and the side frame plates I8 aref spaced Fig. '7 is a sectional, elevational view of one apart, by means of a pair of inside upright end side of the Crusher, the section being taken subplates I9 and 20 welded to the base plates I'I. Stentieliv 0n line 1-1 0f Fia 6 but Showing `50 End plate zo is also weidea i0 the side frame certain parts on said section line in elevation; plates |3 and forms one Side of the crushing Fig. 3 iS a View in plan of the main frame 0f chamber II adjacent the xed crushing roll I2. the ClllSheY; emi Extending between the base plates I'I and weld- Fig. 9 is a view in section, the sectiOn being ed to the lower edge of the end plate 20 is a plate taken on line 9--9 of Fig. 8. 55 2l which co-operates with the base plates I1 t0 form the base of the main frame I0.; The main frame I9 includes a pair of bearing supporting platforms 22 welded to the hereinafter described partition plate 32 and the base plates I1. Extending between and welded to base plates I1 and to the lowermost edge of the end plate I9 is a Y inside end plate 24 there is a top end plate 26. Y

As previously described, each base plate I1 isV welded alongV its inner edge to one of the side frame plates I8. There is a series of partition plates 21, 28, 29, 30, 3| and 32, which extend outwardly from the side frame plates Iiand upwardly from the base plates I1 and are welded both to the base plates I1 and side frame plates I8. Partition plates 21 are also welded to end plate I9. These partition plates 21 through 32 are spaced to provide a plurality of compartments including bearing compartments 33 in which the bearings for the shaft I5 of the fixed crushing roll `l2 are receivedA bythe main frame and bearing compartments 34 in which the bearings for the shaft I6 ofthe movable crushing roll I3.are received. The side frame plates I8 are cut out opposite the bearing compartments 3'3 and y34 at 35 and 36, respectively, to provide openings therein through which the shafts I 5 and I6 extend into the bearing compartments 33 and 34. Extending between each partition 21 and 28 in the plane of the top end plate 26 is a bed plate 31.

Referring now to Figs. 1, 2, 6 and '7 of the drawings, each of the bearing supporting platforms 22 carries a bearing 3'8 which in turn carries a cross shaft 39 which carries at one end a pulley wheel 40 adapted to be driven by a belt driven from a source of power such as an electric motor, not shown. The fixed crushing roll I2'is carried with its axis extending transversely of the crushing compartment or chamber II by bearing assemblies 4I that fit within the bearing compartments .33 and receive Ythe ends of the shaft I5 that extend through the cut-out portions 35 in each side frame plate I8..

Referring particularly to Fig. 7, each bearing assembly 4I includes a self-aligning anti-friction bearing 42that is Yreceived by a pair of complen mentary supporting blocks 43 and V44. Block 43 which supports the anti-,friction bearing 42 rests upon bed members 45 welded to the base plates `I1 and to the partition plates 36 and 3|. Bearing blocks 43 and 44 are of such dimensions that they abut at their sides the partition members 36 and 3 I and the blocks 44 are channeled or grooved lengthwise along their tops to receive bearing block hold-down bars 46 the ends of each of which are received in notches 41 in the partin tion plates 30 and 3|. The bearing block holddown bar 46 for each of the bearings 4I is held in the lengthwise groove in bearing block 44 and in the notches 41 by a top plate 48 which is bolted at one end by bolts 49 into a spacer plate 50 between, and adjacent the tops of the partitions 3| and 32. The opposite end of the top plate 48 is secured by bolts 5I that extend through the bed plates 31.V

Referring now to Fig. 1 of the drawings,r the 75 4 shaft 39 between the pulley Wheel 40 and the adjacent bearing 38 carries a pinion gear 52 which meshes With a large gear 53 carried upon one end of shaft I5 of the fixed crushing roll I2 which end of shaft I5 extends through its supporting bearing assembly 4I beyond the base plate I1 to receive. the large gear 53. Thus it will be seen that'when shaft 39 is driven by the pulley 46, pinion gear 52 will in turn drive the large gear 53 and the fixed crushing roll I2.

The bodily movable crushing roll I3 like the fixed crushing roll I2 is carried transversely of and within the crushing compartment or chamber II to co-operate with the fixed crushing roll I2 for crushing material fed therebetween as the crushing rolls I2 and I3 rotate. The ends of shaft I6 of the movable-crushing roll I3 are carried bybearing assemblies 54 the construction of which is vsimilar in most respects to the construction of bearing assemblies 4I for the shaft I5. Bearing assemblies 54 like the bearing assemblies 4I include bottom blocks 55 and top blocks 56.

In the bottom of each bearing compartment 34 and extending between the partition plates 28 and 29 there are three spaced supporting bars 51, 58 and 59 (see Figs. 3, 4' and V5) which support a pair of spaced bearing strips 69 upon which the bottom blocks 55 of bearings 54 rest and slide. Each bottom block 55 includes a gib or tongue 6I that extends downwardly into the way formed by and between the spaced bearing strips 60. The top block 56 of each bearing 54 is channeled lengthwise along its top surface and is relieved, as indicated at'62 in Figs.'3 and 4, to provide concave semi-circular bearing surfaces 6-3. Each bearing assembly'54 is held down by a bearing hold-down bar 64 which extends in the concave semi-circularbearing surfaces 63 and the ends of each bar 64 are received in notches 65 formed in the partition plates 28 and 29. Hold-down bars 64 are secured to the main frame l0 by the top plate 48 previously mentioned in connection with the hold-down bar 46. It will thus be seen that the bodily movable crushing roll I3 can move in a plane since its shaft supporting bearing assemblies 54 are slidably carried at their bottoms for guided motion upon the bearing strips 6i) by the tongues 6| and lthe top blocks 55 thereof may slide along the hold-down bars 64.

Positioned between each side frame plate I8 and bearing assembly 54 of the movable shaft I6 is a cover or closure plate 66 (best seen in Figs. 6 and '7) which plates have holes snugly receiving shaft I6 Vto move therewith yas the movable crushing roll I3 moves bodily. Plates 66 close the cut-out portions 36 in the side frame plates I8. The closure plates 66 bear against the outside surfaces of the side frame plates I8 and the opposite ends thereof slide through notches 61 formed in the partition plates 28, 29 and 30. (See Figs. 5 and 8.)

The normal proximity of the movable crushing roll I3 with respectrto the fixed crushing roll I2 may be adjusted by means of adjusting mechanism now to be described. Each of the bearing blocks 55 and 55 ofv bearing assemblies 54 is machined so that when the bearing assembly 54 is assembled the blocks t about a collar 68 (see particularly Fig. 4) that is secured to the end of an adjusting screw 69 whereby the screw 69 and collar 68 may rotate within the ico-operating blocks 55 and 56 to adjust the bearing assembly 54 longitudinally between the bearing strips 60 and hold-downbar 64 and consequently adjust the movable crushing roll I3 with respect to the fixed crushing roll I2. Adjusting screw 69 `extends through an opening in partition plate 28 and an opening 1| .in the partition plate 21. Extending between and welded to the outside edge of each partition 21 and 28 is a guide plate 12 (Fig. 5) which carries a pair of spaced bars 13 that form a track or way therebetween that receives a tongue 14 of a circular adjusting nut 15 threaded on the adjusting screw 60. A heavy compression spring 16 abuts the adjusting nut 15 and the partition 21 and urges the screw and consequently the movable crushing roll I3 toward the fixed crushing roll I'2. The outside end of the adjusting screw 69 is-carried within a collared bushing 11 that is received in the opening 1| in the partition plate 21 and the'end of the shaft carries a pair of lock nuts 18 and is squared at 19 to receive a wrench.

From the foregoing description of the screw 69 and its co-operating mechanism it will be seen that when the screw 69 is rotated by means of a wrench attached to its squared end portion 19 the adjusting nut may be moved along the screw 69 to increase or decrease the tension of spring 16. It will also be seen that the lock or jam nuts 18 mai7 be set at a position on the screw 69 to adjust the position of minimum clearance between the movable crushing roll I3 and the xed crushing roll I2.

As previously set forth, the fixed `crushing roll I2 is driven from the shaft 38 through the gears 52 and 53 and the bodily movable crushing roll I3 is driven from the xed crushing roll I2 by a belt and pulley mechanism, best seen in Fig. 2. The driven'shaft I5 of the fixed crushing roll I2 carries a pulley 00 which rotates counterclockwise, that is, in the direction indicated by the arrow and the shaft I6 of the bodily movable roll I3 carries a pulley 8|. lulleys 80 and 8| are herein shown as being of equal diameter.

However, if desired, the diameter of either pulley or 0| may be changed with respect to the other to drive the crushing rolls at different rates of speed relative to one another. The upper block 58 of bearing assembly 54 adjacent the pulley 8| has a bracket 82 welded thereto through a spacer 83. At one end bracket 82 carries an idler pulley 84. Idler pulley 84 is adjustably mounted on the bracket S2 and its `position of adjustment with respect thereto is determined by means of an adjusting screw 85 that extends through an outstanding lug 8E on the bracket 82 and is clamped thereto by means of a pair of nuts 81. It will be seen that as the movable crushing roll I3 moves bodily with respect to the crushing roll I2 the bearing assemblies 54 and idler pulleys 84 will move with it.

Base plate Il of the main frame I0 is provided with a bar 80 (see Fig. 7) that carries a pulley mounting assembly 80 secured at its bottom to the bar 88 and at its top to the guide plate 12 thereabove. Pulley 90 is mounted on a fixed axis relative to the main frame I0 by the supporting assembly 89. A belt 9| is looped or reeved about the pulley 00 over the fixed idler .pulley 90, the pulley 8| of the movable crushing roll I3, and the movable idler pulley 84 carried by the bearing assembly 54. By reference to Fig. 2 it will be seen that the pulley 3| of the .bodily movable crushing roll I3 will rotate in a clockwise direction, as indicated by the arrow, which is opposite to the direction of rotation of the pulley 80 of the fixed crushing roll I2 and since the pulleys 80 and 8| are of the same diameter, the crushing rolls I2 and I3 will rotate at equal rates of speed. It will also be seen that since the idler pulley 84 and the pulley 8| move bodilyas the movable roll I3 moves with respect to the xed crushing roll I2, the required length of the belt 9| at all times remains constant since, as the idler pulley 84 and pulley 8| move to the left for example, the length of the portion 92 of belt 9| will be decreased and that the length of the belt portion 93 between the idler roll 84 and the pulley 80 will be increased an amount equal to that which the belt 4portion 92 is decreased. Thus belt 3| will at all times drive the pulley 8| from the driving pulley 801.

From the foregoing description it will be seen that the distance or clearance between the crushing rolls I2 and I3 may be determined by adjusting the lock or jam nuts l18 and that the bodily movable crushing roll I3 is urged toward the position of minimum clearance with respect to the xed crushing roll I2 by the springs 16. Thus, should a large non-crushable piece of material such, for example, as a piece of iron, enter between the rolls I2 and I3 the movable crushing roll I3 can move away from the fixed crushing roll I2 to permit the non-crushable object to pass between the rolls I2 and I3 by compressing the springs 16 thereby preventing damage to the Crusher.

An important feature of my invention resides in the parallel motion mechanism now to be described that maintains the axis of the movable crushing roll at all times parallel with respect to the axis of the fixed crushing roll I2. The parallel motion mechanism includes a pair of shafts 94 (see Fig. '1) one of which is carried in each of two compartments 95 formed between rpartition plates 29 and 30 at opposite `sides of the main frame I0 (see Fig. 8l. Each shaft 94 extends through an opening formed in a sha-ft support and abutment plate 96 positioned between the partitions 29 and 30 and adjacent the tops thereof. It may be mentioned that the adjacent ends of hold-down bars 46 and 64. abut the plates 96; that the ends of the holddown bars 46 opposite the shaft support and abutment plates 96 abut the spacer plates 50; and that the ends of the shafts 64 opposite the shaft support and abutment plates 95 abut the ends of the bed plates 31. The lowermost end of each shaft 94 extends into an opening 91 in each base plate I1 and partitions 20 and 30 are cut out as at 98 to receive a sprocket wheel 99 spaced upwardly from the base plate I1 by a collar |00. Shafts 94 extend through openings in the top plates 48 and are held against vertical movement relative to the main frame I0 by set screws |0I in the shaft support and abutment plates 96. A second sprocket wheel |02 is carried by each shaft 94 at its upper end which sprockets |02 are spaced with respect to the plates 06 and 48 by bearing collars |03 and are secured thereon against upward movement by a screw and washer |04. Sprocket wheels 09 and |02 are free to rotate upon the shaft 94.

Referring now to that part of the parallel motion mechanism indicated in the lower left hand corner of Fig. 1 and shown in detail at the left side of Fig. 6 and in the upper left hand corner of Fig. 7 of the drawings, there is a pair of yoke members |05, |06 each of which carries between its side members a sprocket wheel |01 mounted upon a shaft |08 that extends between the upper and lower members or tines of the yokes. Each yoke |05 and |06 is provided with `an adjusting screw |09 that extends through yokes |05 and |06 is to permit clearance of the strands of a looped chain hereinafter described.

As Yseen in Fig. 6, yoke members |05 and |06 lie side by side and abut one another and the yokes-as a pair rest upon the bed plate 31. Bed plate 31 is provided with a guide bar |I2 which abuts one side of the yoke member |05 and top end` plate 26 is provided with a guide bar I|3 that abuts one side of the yoke member |06. Thusit will be Vseen that by adjusting the nuts |I on the screws |09 of either of the yoke members and |06 the position of their respective sprockets |01'may be changed with respect to the sprocket |02 on shaft 94.

As seen in the upper left hand corner of Fig. l, the parallel motion mechanism includes a second pair of sprockets ||4 carried by yokes and mounting structure, not shown, but which is identical in construction to that described for yokes |05, |06. The parallel motion mechanism includes an endless chain I|5 so reeved about sprockets |02, |01 and I|4, as to form a double Vstranded U-shaped loop the ends of the legs of which U-shaped loop are formed by the sprockets |02.

With reference to Fig. 1, it will be seen that the U-shaped looped chain II5 includes an outside strand or run I|6 and an inside strand or run |I1 and that if the outside strand ||6 is moved in one direction the inside'strand I|1 will be moved an equal amount in the opposite direction. The ends of shaft I6 of the bodily movable crusher roll I3 are connected to the endless chain I|5 through brackets ||8 carried by bearing assemblies 54. However, they are not connected to the same strand thereof. By reference to Fig. l it will be seen that the bearing assembly 54 seen at the top of the drawing is connected by its bracket IISYto the outside v strand |I| of the chain I I5 and that the bracket IIB of the lower bearing assembly 54 is connected to the inside strand II1. Thus it will be seen that should a non-crushable object be presented to the crushing rolls I2 and I3 the bodily movable crushing roll I3, since'it is resiliently urged toward the fixed crushing roll I2, will move away from the roll I2. In so doing, 0f course, it will move the bearing assembly 54 which is connected to the outside strand II6. This, of course, will move the outside strand II6 t0 the left and, of course, move the inside strand II1 above said bearing assembly 54 to the right an equal amount. On the opposite side of the crusher, of course, the direction of travel of the strands of chain I|5 will be reversed, that is,

' the outer strand I|6 will be traveling to the right and the inner strand |I1 will be traveling jto the left and since the bearing assembly 54 A There is a second parallel motion mechanism 8 substantially identical with the previously described parallel motion mechanism situated within and adjacent the top of the main frame I0. This'second parallel motion mechanism, hown ever, is connected to the bottom blocks 55 of the bearing assemblies 54 Whereas the previously described parallel motion mechanism is connected to the top block 56 of each of said bearing assemblies 54. An endless chain II9 of the second parallel motion mechanism is looped about the sprockets 99 which are directly below sprockets |52 and carried by shafts 94. From the sprockets 99 the strands of the chain I I9 extend rearwardly between the supporting bars 51, 58 and.59 in each bearing compartment 34 to sprockets |20 carried by yoke members I2 I v I 22 which are identical to the yoke members |05 and |06, respectively. It is to be understood, of course, that the chain II9 extends between sprockets |20 situated at the opposite sidesof the main frame I0 to complete a U-shaped loop. Because of the relatively limited space in which the strands of chain |I9 operate adjacent the bottom blocks 55 the bottom blocks 55 are connected to the chain ||9 by a pair of arms |23 (see Fig. 3) which extend through appropriate slots (not shown) in the bearing strips 60 and alongside the chain I9 to which they are bolted. It is to beV noted that whenA the top block 56 of one bearing assembly 54 is attached by means of its bracket I|0 to the inside strand I I1 of chain I I6 the bottom block 55 of the assembly will be attached to the outside strand of chain H9, and vice versa, for the purpose of neutralizing twisting moments on the bearing assemblies 54 when the bodily movable crushing roll I3 is caused to move suddenly away from rthe fixed crushing roll I2.

It may be mentioned that the feed chute ifi preferably includes a pair of side plates |24 (Fig. l) arcuately formed at their lowermost edges so asto extend downwardly between the crushing rolls I2 and I3 and these side plates |24 are removably secured within the feed chute |4 by a plurality of bolts |25. Feed chute I4 also includes a pair of plates |26 that extend thereacross and downwardly toward the rolls I2 and I3 and which are notched along their bottom edges to permit the lugs or teeth |21 of the rolls i2 and' I3 to pass therethrough.

The driving mechanism including the pullei7 wheels 80,'8I, 84 and 90 is covered by a removable cover |28 and gears 52 and 53 are covered by a cover |29. Y Y

From the foregoing description it will be readily apparent that I have provided an improved Y crusher in which a bodily movable crushing element is resiliently urged toward a co-operating crushing element and that the bodily movable crushing element, when required to do so, can Vmove with respect to its xed co-operating element in a plane while Yat all times remaining on an axis that remains either parallel or in a denite angular relationship with respect to the co-operating crushing element, that is, the ends of the crushing roll move in a plane through substantially equal distances because the ends of the bodily movable crushing roll are interconnected by a parallel motion mechanism.

It will also be seen that the axis `of the bodily movable crushing roll which is the axis of its driving pulley 8| remains at all times in the same angular relationship with the axis ofthe driving pulley of the fixed crushing roll I 2, and therefore there will be no tendency for the driving belt 93 to run off of the wheels 80, 8|,y 84,

or 9B, when the bodily movable crushing roll. iii moves with respect to the xed crushing elen ment l 2.

Obviously those skilled in the art may make various changes in the details and arrangement` of parts without departing from the spirit and scope of the invention as dened by the claims hereto appended and applicant wishes therefore not to be restricted to the precise construction herein disclosed.

Having thus described and shown an embodinient of the invention, what it is desired to sen cure by Letters Patent of the United cStates is:

l. A roll crusher including a crushing roll, crushing means (3o-operating with said crushing roll for Crushing material therebetween, bearing means supporting each end of said crushing roll for bodily movement of the crushing roll to and from the co-operating crushing means, and parallel motion mechanism interu connecting the ends of said crushing roll said parallel motion mechanism including sparJ :l wheels and an endless flexible means trained over said spaced wheels and forming a loop having oppositely moving portions, at opposite sides of said roll and extending parallel to the plane of reciprocation thereof, means connecting one of said portions of said endless looped flexible means with one end of said crushing roll and the other said portion of said endless looped exible means with the other end of said crushing roll whereby said roll will move to and from said ofi-operating crushing means with its ends moving through substantially equal distances in the same direction.

2. A roll Crusher including a main frame, a Crusher roll having a shaft extending 'transversely of said main frame, bearing means for each end of said shaft reciprocatably carried by said main frame, means co-operating with said roll for crushing material therebetween, means I lo urging said crushing roll to a position adjacent said co-operating crushing means, and parallel motion mechanism interconnecting said bearings, said parallel motion mechanism including spaced wheels carried by said main frame and a pair of endless ilexible means lying in planes at opposite sides of said bearings and extending parallel to the plane of reciprocation thereof, each endless flexible means being trained over a phrrality of said spaced wheels and each forming a loop having oppositely movable portions lying side by side, means connecting those portions of each of said flexible means adjacent each of said bearings traveling in the same direction thereto whereby said roll can move only to and from said co-operating crushing means with its ends traveling through substantially equal distances in the same direction.

WALTER C. STEINMETZ.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 158,257 .Dobler Dec. 29, 1874i Li22,908 Brewster Mar. l1,

1,356,291 Kennedy Oct. 19, 1920 2,086,659 Armstrong July 13, 1937 2,182,900 Mcllvried Dec. 31, 1939 FOREIGN PATENTS Number Country Date 6,313 Great Britain Jan. 9, 1908 394,546 Great Britain June 219, 1933 OTHER REFERENCES Coal Age (Periodical), back cover page (oute side), June 1, 1940. (Copy available in Scientific Library.) 

